The invention is particularly directed towards deploying a stent graft with a fenestration from which or into which a side arm can be deployed to enter one of the arteries that extends from the thoracic arch. These arteries are the innominate artery, the left carotid artery and the left subclavian artery. The invention will generally be discussed in relation to an endoluminal deployment system to enable branch grafting into the left subclavian artery but the invention may equally apply to the other arteries or to other vessels in the human or animal body.
Throughout this specification the term distal with respect to a portion of the aorta, a deployment device or a prosthesis is the end of the aorta, deployment device or prosthesis further away in the direction of blood flow away from the heart and the term proximal means the portion of the aorta, deployment device or end of the prosthesis nearer to the heart. When applied to other vessels similar terms such as caudal and cranial should be understood.